Process for producing 3,5-dihydroxy 1,2-dioxolanes

ABSTRACT

AND HYDROGEN PEROXIDE WHEREIN R AND R1 ARE ALKYL GROUPS HAVING FROM 1 TO 6 CARBON ATOMS AND R2 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND ALKYL GROUPS HAVING FROM 1 TO 6 CARBON ATOMS. WHEN THE REACTION IS CONDUCTED IN THE PRESENCE OF AN ORGANIC DILUENT IN WHICH THE REACTION PRODUCT IS INSOLUBLE, IT IS DESIRABLE TO USE CONCENTRATIONS OF HYDROGEN PEROXIDE IN EXCESS OF 50% W./W. AND THE USE OF SUCH DILUENTS IS DESIRABLE DUE TO THE FORMATION OF A GRANULAR PRODUCT. THE REACTION MAY ALSO BE CONDUCTED IN THE PRESENCE OF AN ORGANIC SOLVENT SUCH AS AN ORGANIC ACID CORRESPONDING TO THE DIKETONE REACTANT WHICH DISOLVES THE DIOXOLANE PRODUCT. THE USE OF AN ORGANIC SOLVENT IS ADVANTAGEOUS FOR PRODUCING SUBSTANTIALLY PURE PRODUCTS WITH MINIMUM PURIFICATION. THE 3,5-DIHYDROXY1,2-DIOXOLANES ARE USEFUL IN THE POLYMERIZATION OF VINYL COMPOUNDS OR IN THE CROSS-LINKING OF UNSATURATED POLYESTER RESINS.   R-CO-CH(-R2)-CO-R&#39;&#39;   3,5-DIHYDROXY 1,2-DIOXOLANES ARE PREPARED BY REACTING IN THE PRESENCE OF A CATALYTIC QUANTITY OF A BASE, A DIKETONE HAVING THE FORMULA

United States Patent Int. Cl. C0711 13/00 U.S. Cl. 260-3403 18 Claims ABSTRACT OF THE DISCLOSURE 3,5-dihydroxy 1,2-dioxolanes are prepared by reacting in the presence of a catalytic quantity of a base, a diketone having the formula R-C-CH-C-R and hdyrogen peroxide wherein R and R are alkyl groups having from 1 to 6 carbon atoms and R is selected from the group consisting of hydrogen and alkyl groups having from 1 to 6 carbon atoms. When the reaction is conducted in the presence of an organic diluent in which the reaction product is insoluble, it is desirable to use concentrations of hydrogen peroxide in excess of 50% w./w. and the use of such diluents is desirable due to the formation of a granular product. The reaction may also be conducted in the presence of an organic solvent such as an organic acid corresponding to the diketone reactant which dissolves the dioxolane product. The use of an organic solvent is advantageous for producing substantially pure products with minimum purification. The 3,5-dihydroxy- 1,2-dioxolanes are useful in the polymerization of vinyl compounds or in the cross-linking of unsaturated polyester resins.

This invention relates to a process for the production of peroxygen compounds, and particularly, to the production of 3,5-dihydroxy 1,2-dioxolanes. This application is a continuation-in-part of my co-pending application, Ser. No. 798,833 filed Nov. 20, 1968, now abandoned.

The invention provides a process for the preparation of 3,5-dihydroxy-1,2-dioxolanes by conducting a reaction between a diketone and hydrogen peroxide in the presence of a catalytic quantity of base according to the equation wherein R and R are alkyl groups having from 1 to 6 carbon atoms and R is a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms.

The term base is used in the general sense to mean a proton acceptor. The term catalytic quantity is used to mean a quantity which will cause the reaction to proceed more quickly than if it had not been used as evidenced by the time required for crystallization of the reaction product to start. 'It will be appreciated that a soichiometric quantity of hydrogen peroxide may be employed or, if desired, the quantity of hydrogen peroxide may differ from the stoichiometric quantity without departing from the invention.

Diketones suitable for use in the above reaction tend to contain residual but appreciable quantities of an organic acid. Industrial grade acetyl acetone normally contains 1 to grams acetic acid per liter.

3,787,446 Patented Jan. 22, 1974 In certain circumstances, it would be useful to perform the above reaction in the presence of an organic solvent to prevent the reaction product from crystallizing and to enable derivatives of the dissolved reaction product to be prepared by introducing other reactants into the resulting solution. Certain organic acids are very useful solvents for this latter purpose.

However, the presence of an acid in the reaction described above tends to cause the hydroxy groups of the dioxolane reaction product to react with any residual quantities of hydrogen peroxide present and form hydroperoxy groups reducing the yield and introducing impurities. Traces of acid adhering to 3,5-dihydroxy 3,5- dimethyl 1,2-dioxo1ane may cause the formation of shocksensitive trisperoxide.

R and R are usually the same; contain from 1 to 6 carbon atoms and preferably are both methyl radicals. R may be hydrogen or an alkyl radical containing from 1 to 6 carbon atoms, but is preferably hydrogen or a methyl radical.

When the reaction is conducted in the presence of an organic solvent, hydrogen peroxide of at least 50% w./ W. concentration is suitable and concentrations of at least 70% and, especiaally w./w. are preferred. Commercially available hydrogen peroxide is often stabilized by the addition of acid.

The catalytic effect of a base in the process of the present invention exists in the presence of an acid and when the acid is not present in a large quantity, residual base used according to the invention may also help to neutralize residual quantities of the acid, thus also improving the stability of the reaction product.

The use of a base as a catalyst is, however, a critical feature of the invention While the specific diketone used is not. The invention is therefore also applicable to the manufacture of dioxolanes difiering from those mentioned above in for example, having one or more of R, R and R containing more than 6 carbon atoms or in having an extra carbon atom in the dioxolane ring.

The selection of a suitable base as the catalyst is within the skill of the art. Generally moderate bases are preferred. Extremely weak bases, while having some effect, are not preferred since the substantial reduction in reaction time is not obtained, although the yield increases and extremely strong bases such as alkali or alkaline earth metal hydroxides catalyze the reaction, they decrease the yield of dioxolane by decomposition of the hydrogen peroxide unless neutralized prior to drying the products. Nonvolatile inorganic bases, such as oxides or carbonates of alkali or alkaline earth metals, are not preferred because they are more difiicult to remove from the dioxolane product even though they exhibit good catalytic activity.

Amines or ammonia are useful as the base catalyst for practicing the present invention. Suitable amines include primary, secondary or tertiary amines, which may be aliphatic, aromatic or heterocyclic, ethyl amine, n-propyl amine, isopropyl amine, hexyl amine, octyl amine, dodecyl amine, 2-ethyl hexyl amine, 2,9-dimethyl decyl amine, tertiary butyl amine, cyclopentyl amine, cyclohexyl amine, aniline, 0- or p-toluidine, diethyl amine, din-propyl amine, di-isopropyl amine, di-n-butyl amine, methyl aniline, diphenyl amine, triethyl amine, triamyl amine, triphenyl amine and dimethyl aniline. Tertiary heterocyclic amines, for example, pyridine; a lutidine, such as 2,4-lutidine, 2,6-lutidine and 3,4-lutidine; a collidine, such as 0:, 3 and 'y-collidine; and quinoline or alkyl derivatives thereof such as 3-methyl quinoline, 2,6- dimethyl quinoline and 2,3,4-trimethyl quinoline are preferred. These compounds are highly effective catalysts in spite of their relatively low basicity, because they have no decomposing effect on hydrogen peroxide and are not oxidized by hydrogen peroxide. Aliphatic or aromatic amines, particularly if primary or secondary, may be oxidized to some degree by hydrogen peroxide but are, nevertheless, effective catalysts.

reduced by the present invention. This is an important advantage of the invention.

The production of 3,5-dihydroxy 1,2-dioxolanes by a reaction between a diketone and aqueous hydrogen peroxide of at least 50% w./W. concentration according to Preferably the base catalyst issued in a quantity of 0.1 5 the equation to 1.0 mole per 100 moles of ketone. However, larger R quantities up to 5 moles of base per 100 moles of ketone R H can be used particularly where the base selected as catalyst is a weak one. 0 G

When the preparation of 3,5-d1hydroxy 1,2-d1oxolanes (i R2 0 HO 0-0 OH is conducted in the presence of an organic solvent, the whaein R, R1 and R2 are as defined above; the reacfion solvent for exafnple an organic acid Preferably is conducted in the presence of an inert organic medium spends F the dlketone used For K l w the in which the 3,5-dihydroxy 1,2-dioxolane is insoluble in ketene e acetyl acetone: the and preferebly the presence of at least a catalytic quantity of a base is aeenc f and e quanmy of aeld e preferebly suefielem a particularly advantageous embodiment. Preferably the to mamtam the dlexelane Preduet It 15 e diketone is acetyl acetone. The preferred concentrations vantageous tqueat the resultmg sohmon by .Iltroducmg of hydrogen peroxide, identity of diketone, and quantity hydreperexlde such as e hydroperoxlde and a and identity of base are those set forth hereinabove. small quantlty 9 a stwegeeld such H2804 or Hclofi Suitable diluents are alcohols, dioxan or tetrahydroto form a solution contarmng a 3,5-d1alkyl peroxy 1,2-d1- fumn combined with low boiling halogenated hYdrocar, oxolaneiA phlegmatiser Such as a phthalate ester for bons or with unsubstituted hydrocarbons. A mixture of ample dl butyl phthalate, may be added; the acid rem triethyl phosphate and methylene chloride is preferred, by weshmg Wlth an 15% Nacl solution and particularly when the diketone is acetyl acetone. The resulting l of perelfy quantity of diluent used should preferably be such that oxelane y be dnefi',Smee,es'dlhydmxy'lz'dlexelanes the reaction mixture does not solidify during the crystalare soluble in water 1t 1s desirable to use concentrated hylizatiom drogen peroxide in preparing these compounds by the The crystalline precipitate of 3,s dihydmxy ILdioxm above reaction to reduce the amount of dissolved reaclane may be filtered and dried. tion product in a state of dissociation equlhbrlum with In operating the process of this invention, Preferably, the starting mater e the reactants other than the hydrogen peroxide, the diluorder to mmlmlze the dangerqus F F of l cut or solvent if used, are mixed and the hydrogen perdroxolanes, their preparation according to thls invent on oxide slowly added to the mixture which is preferably may be carried Out m the Presence of men hydrophlhe cooled before addition of the hydrogen peroxide. Coolsolvents, such as trialkyl phosphates, alcohols, glycol, and mg the mixture to a temperature below about 10:) C is glypol hers and esters t! mmtures thereof Such advantageous and preferably the reaction vessel is cooled hmons Show excellent stablhty. so that the reaction temperature does not exceed 25 C.

In the absence of an organic solvent for the reactlon The Present invention also providgs 35 dihydmxy Product hydrogen perfxide of 50% dioxolanes and particularly 3,5-dihydroxy 3,5-dimethyl or higher in the macho tends B .mmal 40 1,2-dioxolane whenever produced by the process described delay, a relatively quick crystalllzatlon, whlch 1s difiicult herein and the use of Such dioxolanes in the polymeriza to control. When the diketone is acetyl acetone and the tion of vinyl compounds or in the crossJhlking or mam reaction is conducted in the absence of a solvent with a rated polyester resins concemliatmn of 50% or more a Send damp mass The following examples are presented to illustrate the of reaeton e e results present invention. Examples 7 to 25 demonstrate the in- If e reaetlen is conducted usmg e vention while Examples 1 to 6 are presented for comcentratron or higher of hydrogen peroxide in the presence Parative purposes of an organic diluent in which the reaction product is not soluble the consistency of the reaction mixture is im EXAMPLES Proved and tends to form a 311mm Product 5 200.2 g. (2.0 mol) of industrial grade acetyl acetone was The selection of a suitable diluent involves a number cooled b salt/ice or water i a vessel surrounding th of considerations amongst Whidl are the Solubility char reactor to the temperature reported in Table I and 2.0 mol acteristic mentioned above; the desirably of the diluent f H 0 of h reported u ti was dd d d by to be hydrophilic so as to remove small am of drop with stirring. The end point of the reaction was apter and/0r residual hydrogen peroxide which y be parent when 3,5 dihydroxy 3,5-dimethyl-dioxolane-l,2 Present from the reaction; and the desirability of being ceased crystallizing and the temperature of the reaction reasonably volatile to enable easy removal from the solid, mixture returned to th t of h b h, Th li id was isolated reaction Product y y A mixture of drained ed the crystalline product which was washed and ethyl phosphate and methylene chloride is an example of then dried for a period of 48 hours in an atmospheric air a suitable diluent. However, common reduction of the redrying cabinet. The results of the reactions are reported action rate caused by the use of a diluent is considerably in the following table.

TABLE I Time in minutes from starting H202 addition H2 HrOzaddition at End of coneenconversion Yield 01 Bath tration, Max. Start of reaction pure prod- Ex. temp, weight Time temp, crystal- Purity, product, No. 0 percent (min.) C. lization Minutes Hours percent percent Remarks 1- 2-5 50 25 3 225 6 99. 3 81. 4 Wash as in example.

-..-. 10 50 15 17 1 2 6 100 87.8 Crystallizable very hard had to be softened with a triethyl phosphate/011201: mixture before passing to the filter.

3- 7-10 60 33 14 i 180 10 5 94. 6 87. 9 Single solid mass. softened with other. 4... 7-10 70 26 15 180 50 6 Rock-hard product. Could not; be transferred even with solvent was used.

3 Subsequently stirred for a further hour.

5 EXAMPLES 5-23 200.2 g. (2.0 mole) of industrial grade acetyl acetone and 130 ml. of technical methylene chloride were placed in a reactor and brought to the initial temperature indi- 6 EXAMPLE 25 14.4 g. of 82.8% H (0.35 mole) was added dropwise while stirring at a temperature of 12 C. and over a period of 15 mins. to a solution of 250 g. (0.25 mole) cated in Table 11 by a cooling vessel surrounding the reof technical grade acetyl acetone in 60 m1. of glacial acetic actor. The amount of base reported in Table II was then acid containing 0.1 mol percent 2,4,6-collidine. Stirring added as a solution in water on methylene chloride adwas continued for a further 30 mins. 50.6 g. of 89% (0.50 justed so that the total amount of solution remained conmole) technical grade t.butyl hydroperoxide was then sistant. A mixture of 2.0 mol of 83.7% H 0 81.3 g.) added, followed by the dropwise addition of 12.5 ml. of and 40 g. of industrial grade triethyl phosphate was added 2 N sulphuric acid in glacial acetic acid. The temperature drop by drop with stirring and continuous cooling to enof the mixture was then raised to 30 for 1 hour. sure, for safety reasons, that the internal temperature did After the addition of 70 g. of dibutyl phthalate (as a not rise above 25. Therefore, the addition had to be interphlegmatising agent) the mixture was diluted with 200 ml. rupted on occasion. The end of the reaction was reached of nalt solution. The separated organic phase was when the internal temperature corresponded to that of 15 Washed until it was neutral. After drying over sodium the cooling vessel. In order to ensure complete crystallizap ate, 124.7 g. of phthalatc solution containing 46.6% tion, stirring was continued for 1 hour (Note: Triethyl y p fyy di0101ane-L2 (83.6% phosphate was d to dil h H 0 t id b tter of the theoret1cal y1eld( and a 0.8% t.butyl hydroperoxide control of the addition in this small-scale experiment but C ent was obtained. it is preferable to place triethyl phosphate in the receiv- What IS a med 1st I ing vessel because of the inherent danger in mixtures of A pfocessfor P p a y Xy L high concentrations H 0 with organic compounds.) lane correspolldlng t0 e formula The mixture was drawn off using a suction filter and the crystals washed first With 120 ml. of a mixture of triethyl phosphate and methylene chloride (1:30 v./v.) and then R 1 with 120 ml. of methylene chloride and dried for 48 hours in a fresh air-oven. The results of Experiments 5-23 are reported in Table 11. H0 O O 0H TABLE II Time in minutes from starting H105 addition of- Start of crystalli- H207 addition atzation End of conversion reaction Yield p M012 T t Max. M Approgx- M R url of pure ercen 1me emp. 1nrma e naw P t d t, Base of base (min) 0'. utes hours utes Hours percent perce t l grc t Comparison None 15 62.3 100 62.3 n-Methylpr011id0ne-... 5 .0 10 68 .7 100 68 .7 .6-c0llidine--.. 1.0 85.5 100 85.5 2.4.6-(30111111118 0.1 47 86.0 95.8 82.0 2.4.6-collidine plus 10 0.1 14 83.5 98.7 82.0

ml. acetic acid. 2.6-lutidine 0.1 13 84.9 100 84.9 Pyridine 0.1 12 84.3 99.5 83.7 8 Tri-isopropanolamine- 0.1 39 79 .5 100 79 .5 021515 N 0.1 52 82.5 100 82.5 7 omnygom): 0.1 19 22 80.0 92.5 74.9 Piperidme 0 .1 24 20 75 .5 98 .9 75 .0 10 do 0.1 43 I 26 7e .5 100 78 .5 8-9 Monoethanolamine 0.1 13 18 83.5 97.3 81.5 9 Imidazol- 0.1 39 I 24 79.5 98.5 78.2 9 -do- 1.0 45 I 25 59 .0 98.9 58.0 8-9 N51,--- 1.0 46 7 24 82.7 100 82.7 9-11 NazOO 0.1 51 7 27 24.0 98.3 24.2 19 NaOH- 0.1 32 25 37.6 99.1 37.4 10 NaOH 0.1 88 25 55.3 98.7 55.0

Com arisonexam leusin ana id amide. Dec siti n durl i f 285 1 n1 2 lmm diate rapid ee in t emper ature, therefore slow dropwise addiof dry $052101: emaine i i dry Hg 0 g o damp product 0 y 66 g tion with interruptions to prevent exceeding the 25 temperature limit. 4 Decomposition during drying: of 307 g. of damp product only 101 g.

of dry product remained. EXAMPLE 24 which comprises reacting in the presence of a catalytic Following the procedure of Examples except that, quantity of a base, a dlketone having the formula following completion of the reaction and before drawing R-C-CH-(fi-R off the mixture through the suction filter, the reaction mixa o aYii i'b s dlis e gfdsvi be l 0 97i :0 :523:1 7 1: and hydrogen peroxide wherein R and R are alkyl groups g 1 P having from 1 to 6 carbon atoms and R is selected from xamp e the group consisting of hydrogen and alkyl groups having Fxamnh 1 24 2 21 from 1 to 6 carbon atoms.

2. A process according to claim 1 wherein the base is 232 temp C NA NA i -5 selected from the group consisting of an alkali metal oxide, M018 percent base 2 2 an alkaline earth oxide, an alkali metal hydroxide, an fli z 0111211111111? 45 alkaline earth hydroxide, an alkali metal carbonate, an

2s 27 alkaline earth carbonate, ammonia and an amine.

Tim i utes from startin H 0 addition:

; gtfifcrystamzamnnmins 15 16 3. process according to claim 1 wherem the base is R b. 121136. of comiersion reaction, minutes 815g 217% a tertiary heterocychc amine.

wy .p m 4. A process according to claim 1 wherein the base is P t t 97-9 98-3 y i gia br ii figg mauce emen 85.9 24.2 selected from the group consrstmg of pyridine, lutrdme,

1 This example includes a step of neutralization prior to filtration. colhdme qumohne alkyl (.lenvauves i 1; 1D(t5:0mposition during drying reduced 285 grams of damp product to 5. A process according to clalm 1 wherem the base 15 0 y grams.

an amine selected from the group consisting of primary,

secondary and tertiary aliphatic, aromatic and heterocyclic amines.

6. A process according to claim 1 wherein the base is selected from the group consisting of pyridine, triisopropanolamine, triethylamine, phenyl dimethylamine, piperidine, monoethanolamine and imidazole.

7. A process according to claim 1 wherein the base is ammonia.

8. A process according to claim 1 wherein the base is used in a quantity of 0.1 to 5.0 moles per 100 moles of said diketone.

9. A process according to claim 8 wherein the base is used in a quantity of from 0.1 to 1.0 mole per 100 moles of said diketonc.

10. A process according to claim 1 wherein the reaction is conducted in the presence of a quantity of an organic solvent sufficient to dissolve the 3,5-dihydroxy 1,2- dioxolane being prepared.

11. A process according to claim 10 wherein the organic solvent is an organic acid having the formula RCOOH wherein R is an alkyl group having 1 to 6 carbon atoms.

12. A process according to claim 11 wherein dioxalane is 2,5-dihydroxy 2,5-dimethyl 1,2 dioxolane and the organic solvent is acetic acid.

13. A process according to claim 1 wherein the reaction is conducted in the presence of a hydrophilic organic diluent, said 2,5-dihydroxy 1,2-dioxolane is insoluble therein and said diluent is sufliciently volatile to be vaporized from the 2,5-dihydroxy 1,2-dioxolane by drying at a temperature below the decomposition temperature of said dioxolane.

14. A process as claimed in claim 13 wherein the organic diluent is a mixture selected from the group consisting of methylene chloride with triethyl phosphate, an alcohol with a hydrocarbon and dioxane and tetrahydrofuran with a hydrocarbon, said hydrocarbon being selected from the group consisting of low boiling halogenated and unsubstituted hydrocarbons.

15. A process according to claim 14 wherein the quantity of organic diluent is suflicient to prevent the reaction mixture from solidifying.

16. A process according to claim 10 wherein hydrogen peroxide is an aqueous solution having a concentration of at least w./w.

17. A process for the preparation of 2,5-dihydroxy 2,5- dimethyl 1,2-dioxolane which comprises reacting acetylacetone and at least a 50% w./w. hydrogen peroxide solution in the presence of a catalytic quantity of a base and suflicient acetic acid to maintain said 2,5-dihydroxy 2,5- dirnethyl 1,2-dioxolane in solution.

18. A process as claimed in claim 17 wherein the base is selected from the group consisting of pyridine, lutidine, collidine and quinoline, is present in 0.1 to 1.0 mole per moles of acetyl acetone and the reaction is conducted in the presence of an organic diluent comprising a mixture of methylene chloride and triethyl phosphate.

References Cited FOREIGN PATENTS 1,800,228 7/1969 Germany 260-3403 ALEX MAZEL, Primary Examiner I. H. TURNIPSEED, Assistant Examiner 

